Growli

USDA hardiness zone lookup

Milwaukee, WI — USDA Zone 5b

Milwaukee, Wisconsin · 168-day growing season

Frost dates and growing season in Milwaukee

USDA hardiness zoneZone 5b
Average last spring frostMay 1
Average first fall frostOctober 16
Growing season length~168 days
Temperature range (F)-20 to -10°F
Temperature range (C)-29 to -23°C

All of Milwaukee's mapped ZIP codes fall in the same hardiness band, Zone 5b.

These are 50%-probability averages modeled from Milwaukee's USDA hardiness zone and regional climate normals — not a single-station reading. In a typical year the last spring frost will have passed by May 1, but a colder-than-average year can run 1-2 weeks later. Plant tender crops (tomatoes, peppers, basil) once both soil and night temperatures are consistently warm — a thermometer beats the calendar.

Growing season in Milwaukee

Milwaukee, Wisconsin sits in USDA Zone 5b, with roughly 168 frost-free days between an average last spring frost around May 1 and a first fall frost around October 16. That is a standard temperate season — most common vegetables finish comfortably, and a single main planting plus one succession round works well. Milwaukee lies near 43.0°N; higher-latitude gardens get longer midsummer days but a tighter shoulder season at this zone. As a large metro, the built-up core typically runs up to half a zone warmer than outlying suburbs through the urban heat-island effect — sheltered city gardens often push tender crops a little earlier than the average suggests.

What grows in Milwaukee

Milwaukee falls in USDA Zone 5b, so the same hardiness constraints apply as the full Zone 5 guide. Vegetables, herbs, and fruit trees rated to Zone 5b (or hardier) will overwinter here in a typical year.

What to plant in Milwaukee this week

Milwaukee's last frost is around May 1. This is the spring transplant window — start tomatoes and peppers indoors if you haven't, and direct-sow cold-tolerant crops now.

Full planting calendar for Milwaukee

Crop-by-crop sowing, transplant, and harvest dates calibrated to zone 5 averages:

ZIP codes in Milwaukee

Drill down to the precise frost window and planting calendar for a specific ZIP in Milwaukee:

Local microclimate notes

Zone tables give you the average — but Milwaukeegardens vary. South-facing walls and paved areas can run a full half-zone warmer than the published rating. Low-lying spots, frost pockets, and shaded north sides can run colder. If you've gardened here a few seasons, your own frost record — the last time you actually got frost damage — beats any national average.

Source and methodology

Hardiness zone from the USDA Plant Hardiness Zone Map (2023 revision). Frost-date and growing-season figures are modeled from Milwaukee's USDA hardiness zone and regional NOAA 1991-2020 climate normals — zone-level estimates, not a per-station record, so treat them as planning guidance and confirm against your own local frost history. Crop recommendations draw on US Cooperative Extension references, curated by the Growli editorial team. Last reviewed June 2026.

Other cities in Wisconsin

Related guides